Structure of Neurones & Glia Flashcards Preview

Physiology and Neuroscience > Structure of Neurones & Glia > Flashcards

Flashcards in Structure of Neurones & Glia Deck (43):
1

What are the 3 parts of a neuron?

Cell body/ soma
Dendrites- input
A single axon- ouput

2

What are dendrites and axons are sometimes called collectively?

Neurites

3

What is contained within the soma?

Nucleus
Perikaryon

4

What is perikaryon?

Cytoplasm of a neuron

5

What organelles of the cell body are found in the neuron?

Nucleus
Ribosomes
Golgi apparatus
Microtubules
Mitochondria
Lysosomes
Lipofucin bodies

6

What is the nucleus responsible for?

Contains DNA, replicate cells
Most adult neurons (after the age of 7) do not replicate- DNA involved only in protein synthesis
Protein made by transcription and translation (ribosomes)

7

What are ribosomes responsible for?

Translation
Most commonly associated with endoplasmic reticulum (ER)
Rough ER or Nissl bodies (making proteins and peptide sequences)

8

What is the golgi apparatus responsible for?

Protein assembly completed here

9

What are microtubules responsible for?

Cell body, dendrites and axon
Transporting packaged proteins
Forms part of the cytoskeleton (gives neuron some degree of rigidity)

10

How many neurons are in the mitochondria and what is it's job?

Numerous in neurons
Supply energy

11

What are lysosomes responsible for?

Break down organelles

12

What are lipofucin bodies for?

Contain all neurons rubbish
Electron dense
Waste products in ‘old’ cells

13

What happens to lipofucin bodies as people get older?

As you get older your body obtains more lipofucin bodies

14

What is the role of dendrites?

Continuation of the cell body
Contain free ribosomes and mitochondria
Form branching patterns like trees
Synapses are formed on dendrites
Some synapses on spines

15

What is the role of axons?

Unique to neurons
Specialised for transmission of electrical impulses
Can be up to 1m in length

16

What are the part of the axon?

The axon hillock
Axon proper
Axon collaterals
Axon terminal

17

What does the axon hillock do?

Merges from soma
Generates electrical impulse
Causes neuron to fire

18

Where is the axon proper?

Long part of the axon
Emerges form axon hillock

19

Where are the axon collaterals?

Branch from the axon

20

What are the two cells that make up the brain and the spinal chord?

Neurons
glia

21

What are axons terminals?

Form swelling or boutons
Make synapses

22

What does an axon not contain?

Ribosomes

23

How do axons transport proteins?

Along microtubules

24

What are the ways of axonal transport in a neuron?

Axoplasmic transport (up to 1000mm/day)
Axoplasmic transport- both directions
Away from the cell body (anterograde transport)
Towards the cell body (retrograde transport)

25

What are the reasons for retrograde transport?

To get rid of things of no values
Some molecules can convey messages from axon terminals to cell body (i.e. enzyme requirement)

26

What is the composition of the nerve cell membrane?

Acts as a membrane
Consists of a phospholipid bilayer
Protein molecules embedded in the membrane confer unique properties
Allow ions to pass in or out of the cell selectively i.e. semi permeable membrane

27

How can neurons be classified?

Number of neurites
Shape
Connections
Axons
Neurotransmitters

28

What are the different number of neurites which can be classified in neurons?

Unipolar
Bipolar
Multipolar

29

What are the different shapes neurons can be?

Pyramidal
Sellate- star shaoe

30

What are the different connections for the classification of neurons?

Primary sensory neurons
Moto neurons
Interneurons

31

What are primary sensroy neurons?

Connections with sensory neurons surfaces of the body

32

What are the moto neurons?

Connections with muscles

33

What are the interneurons?

Connections with other neurons

34

How can axons classify neurons?

Golgi type I- long axons
Golgi type II- local axons

35

How can neurotransmitters classify neurons?

E.g. cholinergic- contains acetylcholine

36

How much of cells in the brain are glia?

90%

37

What are the 3 principle classes of glia?

Astrocytes
Oligodendrocytes
Microglia
Astrocytes and oligodendrocytes= macroglia

38

What are astrocytes?

Star shaped
Most numerous type of glia
Few organelles

39

What is the function of astrocytes?

Function is not fully understood
Provide mechanical and metabolic support
Repair process (nervous system damaged, cause scar over and this is impenetrable, stops infection)
Regulate flow of ions and molecules in extracellular fluid

40

What are Oligodendrocytes?

Many organelles and microtrubules

41

What is the function of oligodendrocytes?

Make Myelin (fatty substance which rolls itself around axons, insulting it and allowing conduction of axons to be increased)

42

What is myelin?

Lipid sheath around axons
Electrically insulates axons, not continuous
Node of Ranvier
Peripheral nervous system- myelin formed by Schwann cell

43

What are microglia?

Microglia are really phagocytes, i.e. they remove waste.
About 100,000 neurons in your CNS die every day and microglia remove the debris.